1. Field
The following description relates to a bulk acoustic wave resonator.
2. Description of Related Art
In recent times, in order to efficiently use limited available frequency bandwidths, a band gap between used frequency bands has been decreased. In order to decrease interference between frequency bands caused by the deceased band gap, a bulk acoustic wave resonator having an increased quality factor (QF) has been widely used.
In addition, in order to increase data transmission amounts and data transfer rates, bulk acoustic wave resonators must have broad bandwidths. To this end, an electro-mechanical coupling coefficient (kt2) value of such bulk acoustic wave resonators must be increased.
In general, the QF and kt2 values of bulk acoustic wave resonators may have a conflicting relationship. Therefore, a technology capable of increasing the QF value or kt2 value of bulk acoustic wave resonators is desirable.